Tell your prospects you have Zero Quality Control and they will likely pass over you for your competitor. But Zero Quality Control is exactly what any process should strive for and can achieve with an understanding of source inspection and Poka-yoke systems. Poka-yoke is Japanese and roughly translates to mistake-proofing.
Quality control in many companies can be defined as the corrective actions taken to manage defects. An error occurs causing a defect, information on the defect is gathered and fed to quality control, and corrective action is taken. In a Zero Quality Control environment an error occurs, feedback takes place at the error stage and corrective action is taken before a defect occurs. The underlying premise is the distinction between error and defect.
An error is the action or circumstance that causes the eventual or immediate defect. For example, plate scumming or smearing which results in ink on the non-image area of the substrate is caused during a press stop when the non-image area of the plate dries and becomes sensitized to ink. The error is the dry non-image area. The defect is ink on the page in the non-image area. There are many reasons why this error occurs, but identifying the error before the defect occurs and instituting corrective action is at the heart of Zero Quality Control.
Poka-yoke systems can be employed to identify errors. Poka-yoke systems do not need to be expensive, nor do they need to be purchased. Poka-yoke systems can be checklists. Checklists are used to prevent one from forgetting a step in the process. Forgetting the step is the error. The checklist identifies the error and prevents the defect. A checklist may accompany a job bag with items on it like proof approved, stock ordered, scheduled for production, outside purchases ordered, etc. Without a signed proof, for example, a defect of misspellings, wrong colors, or wrong stock may work its way into production. The checklist, implemented and managed properly, can prevent these defects by calling out the error.
Poka-yoke systems can also be more complex. Prism’s QTMS iQ Web System has a poka-yoke device in its counting system. Counting hardware is not infallible; therefore iQ software compares the counts at multiple points throughout the press. When the counts do not match, a signal is presented to the crew and the proper good copy count is chosen until the discrepancy is found. The error is a bad count at one point along the process. The defect is an inaccurate good copy count. Signaling the error prevents the defect.
For further reading, I highly recommend Zero Quality Control: Source Inspection and the Poka-yoke System, by Shigeo Shingo, Productivity Press.
Toyota and the PIA Continuous Improvement Conference
On April 5th I had the opportunity to attend the Printing Industries of America’s Continuous Improvement conference in Lexington, Kentucky. The highlight of the conference, by far, was an in depth tour of Toyota Motor Manufacturing Kentucky, TMMK, in Georgetown. This 176 acre building is massive. The process starts from rolls of sheet metal and ends with new Camrys, Solaras, Avalons, and Venzas.
We saw firsthand the application of Poka-yoke systems through the use of the Andon cord and corresponding board.
The Andon cord runs the length of the production line and is pulled by any employee to signal an error, defect, or any other production issue. The cord triggers a light board that directs team members, team leaders, and group leaders to the area to solve the issue. The Andon cord can and does stop the entire production line. The cord is pulled tens of thousands of times per shift and employees are encouraged and congratulated when the cord is pulled.
The production line is built from teams of up to five employees that rotate their jobs every couple of hours. One of the five is a team lead, multiple teams have a group leader, and multiple groups have a manager. The plant runs two shifts with two hours between shifts for overtime. Breaks and lunch are plant wide and the entire production line stops during these times.
The tour was complemented by supporting seminars of the Toyota Production System. If you were not one of the close to 200 attendees at this year’s conference, I highly recommend attending next year.
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